线粒体作为氧化磷酸化、三羧酸循环的位点，在植物代谢，生长发育和对环境适应中起重要作用。研究表明线粒体功能受损会导致胚胎败育，也会影响植物的光合能力；在衰老、感病、干旱、盐渍、受伤的植物组织中，交替途径（AP）和磷酸戊糖途径（PPP）均会加强。青稞是青藏高原最具特色的农作物，长期对高原环境的适应使其形成了一系列与之相适应的遗传特性，表现出比一般大麦更高的胁迫耐受性。目前对呼吸代谢在青稞生长发育及对高原环境适应的功能与调节机理知之甚少。本项目旨在筛选、克隆青稞AOX家族基因，查明其表达模式、功能与调控机理；进而探讨AOX与G6PDH在青稞逆境响应中的信号转导途径，及AP和PPP与光合作用的相互关系与作用机制，并揭示其生物学意义。该项目首次系统地探讨AP和PPP在青稞生长发育与逆境适应中的作用与调节机理，项目的完成有助于阐释青稞适应高原环境的抗逆机制，可为作物抗逆高产的分子遗传育种提供理论依据。

Mitochondria, the organ for oxidative phosphorylation and tricarboxylic acid cycle, play important roles in plant metabolism, growth and development, as well as adaptation to environmental stresses. Studies indicate that mitochondrial dysfunction lead to embryo abortion and affect photosynthesis. The alternative pathway (AP) and the pentose phosphate pathway (PPP) were increased in plant tissues suffering environmental stresses, such as senescence, pathogen, drought, saline and mechanical injury. Highland barley is a typical and most important crop in Qinghai-Tibet Plateau region. Due to its long-term adaptation to plateau environments, highland barley has higher tolerance to stresses than barley. At present, the functions and regulatory mechanism of respiratory metabolism in growth, development, and adaptation to plateau environments in highland barley are still unclear. In this project we will focus on the screening and cloning of AOX genes from highland barley; decipher the expression patterns, functions and regulation of these genes; investigate the signal transduction mechanism of AOX and G6PDH in adaptation to stresses in highland barley; resolve the relationship and mechanism among AP, PPP, and photosynthesis. For the first time, we systematically explore the action and regulatory mechanism of AP and PPP in the growth, development, and stress adaptation of highland barley. Completion of this project will contribute to understanding the mechanism of highland barley tolerance to plateau environments and will also provide the theoretical basis for molecular breeding in stress resistance and high yield in crops.